The invention relates to an electrode for an electrical discharge gap and consisting of a metallic composite material wherein tubes having a high burn-off resistance are embedded in a matrix material of high electrical conductivity and are filled with a core material. An advantageous method of producing such electrode is also provided.
Electrical discharge spaces or gaps are often used as switching means. Other possible uses include the initiation of required combustion processes, the limitation of flash-over voltage and the facilitating of required spark or gas discharges.
For the purpose of these uses, the electrodes are so formed and arranged that an optimum operating range is established and that the necessary ionization of the discharge space occurs at a relatively small voltage difference.
DE-PS 566 633 describes a center electrode of a spark plug wherein wires made of a material, e.g. tungsten, that is difficult to vaporize, are embedded in a matrix material, such as chromium or cobalt, that is relatively easily vaporized. In practice, the more easily vaporized component is first removed so that the projecting tungsten wires cause a corresponding compression of the field and therefore facilitate the ignition process.
A known component for limiting voltage is the noble-gas surge arrestor, the electrodes of which are enclosed in a noble-gas atmosphere (helium, neon, argon, keypton, xenon). In a known arrangement, a radioactive preparation is present in the zone of the discharge space and this preparation pre-ionizes the gas space to an appropriate extent and thus makes it possible for a low ignition voltage and a specific operating range to be obtained. Avoidance of the irradiation of the surrounding area that is associated with this system would be desirable.